Fluid working machines are employed in vehicles such as fork-lift trucks, loaders and excavators. Many such vehicles include hydraulic actuators, under operator control. In recent years some vehicles have been built with hydraulic drive transmissions, in which an internal combustion or electrical engine drives a hydraulic pump which delivers hydraulic fluid to hydraulic motors associated with each wheel.
U.S. Pat. No. 4,223,595 discloses a hydraulic motor having a plurality of drive rods arranged along a circumferential direction of an eccentric cam rotating with a rotation shaft. The drive rods are connected to corresponding pistons reciprocating in cylinders. In this hydraulic motor, by allowing an end of each drive rod to contact the eccentric cam, a reciprocating motion of the piston is converted into a rotation motion of the eccentric cam. Particularly, at one end of each drive rod, a holding member for holding a flange part is attached. The flange part of the holding member attached to each drive rod is fixed from outside by a ring member extending along the circumferential direction of the eccentric cam, thereby preventing the pistons from coming off from the eccentric cam.
U.S. Pat. No. 4,629,401 discloses a fluid working machine equipped with a spring member for pressing an end of each drive rod against the eccentric cam. In this fluid working machine, an end of the spring member is fixed to a nearby component and thus, the contact between the drive rod and the eccentric cam is maintained, thereby retaining the drive rod against the eccentric cam.
DE 2915239 discloses a fluid working machine equipped with a connection member for physically connecting the drive rod and the eccentric cam so that the drive rod stays in contact with the eccentric cam.
US 2006/0110276, discloses a fluid working machine that is designed in a way to maintain contact between the drive rod and the eccentric cam by pressing the drive rod against the eccentric cam using an elastic C-shaped member.